1. Field of the Invention
The present invention relates to a Plasma Display Panel (PDP) and a driving method thereof.
2. Description of the Related Art
Recently, flat panel displays, such as Liquid Crystal Displays (LCDs), Field Emission Displays (FEDs) and PDPs, have been actively developed.
The PDPs are superior to the other flat panel displays with regard to their high luminance, high luminous efficiency and wide viewing angle. Accordingly, the PDPs are being used as a substitute for conventional Cathode Ray Tubes (CRTs) for large-screen displays of more than 40 inches.
The PDPs are flat panel displays that use a plasma generated by a gas discharge to display characters or images. The PDPs include, according to their size, more than several tens to millions of pixels arranged in the form of a matrix. These PDPs are classified as Direct Current (DC) PDPs and Alternating Current (AC) PDPs according to the driving voltages supplied thereto and the discharge cell structures thereof.
The DC PDP has electrodes exposed to a discharge space, thereby causing a current to directly flow through the discharge space during the application of a voltage to the DC PDP. In this connection, the DC PDP has a disadvantage in that it requires a resistor for limiting the current. On the other hand, the AC PDP has electrodes covered with a dielectric layer that 1I naturally forms a capacitance component to limit the current and to protect the electrodes from the impact of ions during a discharge. As a result, the AC PDP is superior to the DC PDP in regard to an operating lifetime.
A conventional power supply for such a PDP includes, at its input stage, a Power Factor Correction (PFC) circuit that receives input power from an AC power source and corrects a power factor of the input power to meet a power factor condition. As a result, the power supply supplies stable power to the PDP with the PFC circuit.
That is, upon receiving a rated AC input voltage, the PDP power supply supplies a basic voltage to each element of the PDP. A video signal processor outputs a PFC enable signal, or a signal for turning on a relay in the PDP power supply, which is then input to the power supply.
In response to the PFC enable signal, the PDP power supply sequentially outputs a voltage for video signal processing, a driver switch driving voltage and a PDP driving voltage so that the PDP can operate normally.
The conventional PDP power supply includes the AC power on sequence for driving the PDP, as mentioned above, but does not include an AC power off detector or a sequence for performing a PDP power off operation when the AC power is turned off, and rather senses the AC power off state by merely detecting a standby voltage.
As a result, a driving circuit may be damaged due to an incomplete operation sequence of the power supply during a transient period, such as when the PDP is turned on and off, when the PFC is enabled after the relay in the power supply is turned on, when the PFC is disabled after the relay in the power supply is turned off, or when the relay in the power supply is repeatedly turned on and off.
In detail, during a transient period of the operation of the PDP set, a driving circuit that outputs a driving waveform may be damaged and the picture quality of the PDP may be degraded, due to a timing mismatch between a video signal processing circuit that outputs a video signal and the driving circuit and an imbalance of charge and discharge times during repeated charge and discharge periods of a storage capacitor in the driving circuit, thereby degrading the reliability of the product.